1. Field of the Invention
This invention relates to a Venetian blind, and more particularly to a cord-winding device for a Venetian blind having a brake unit and a pull cord unit that is not directly operated.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a Venetian blind disclosed in Taiwanese Utility Model Patent Publication Number 363667 includes a head rail 1, a bottom rail 2, a plurality of slats 3, two pull cords 4, a winding unit 5, and a positioning unit 6. The winding unit 5 includes a casing 501 disposed within the bottom rail 2, two cord-winding members 502 disposed rotatably within the casing 501, and two spiral springs 503 connected between the cord-winding members 502 and the casing 501. Each of the cord-winding members 502 has a winding portion 504 permitting the corresponding pull cord 4 to be wound thereon, and a engaging portion 505 formed with continuous teeth. The positioning unit 6 includes a braking member 601 and a plurality of springs 602 disposed between and abutting against the casing 501 and the braking member 601. The braking member 601 has two rack portions 603 meshing with the engaging portions 505.
When it is desired to close the slats 3, the braking member 601 is pressed to remove the rack portions 603 from the engaging portions 505. At this time, if the bottom rail 2 is pushed upwardly, the pull cords 4 will be wound around the cord-winding members 502 by virtue of return force of the spiral springs 503, so that the slats 3 are superposed on the bottom rail 2. Conversely, if the bottom rail 2 is pulled downwardly, the pull cords 4 are unwound from the cord-winding members 502 so that the slats 3 are opened. When the bottom rail 2 is lowered to a desired height, the braking member 601 is released to allow the rack portions 603 to engage the engaging portions 505 to thereby stop rotation of the cord-winding members 502. In this manner, the bottom rail 2 can be maintained at any desired height.
As such, the positioning unit 6 is operable to control rotation of the cord-winding members 502. However, in actual use, since the winding unit 5 and the positioning unit 6 are disposed in a middle portion of the bottom rail 2, and since the user needs to press the braking member 601 and push upwardly or pull downwardly the bottom rail 2 with one hand, the bottom rail 2 cannot be held in a balance manner. As a result, the cord-winding members 502 cannot wind the pull cords 4 synchronously, so that the bottom rail 2 is apt to recline, thereby resulting in inconvenience during use and operation.